Anti-Thyroid EIA

Overview

Kallestad™ Anti-Thyroglobulin (Anti-Tg) Autoimmune EIA

Clinical Utility

Thyroglobulin (Tg), thyroid peroxidase (TPO), and the TSH receptor are considered the major autoantigens associated with chronic autoimmune thyroiditis. Clinical diagnosis is usually based on the presence of serum or plasma autoantibodies to Tg and TPO. In Graves' disease (chronic primary hyperthyroidism), the TSH receptor is the antigen most directly involved in clinical manifestations of the disease.1

Anti-Tg autoantibodies are predominantly of the IgG class. They are detected, often with TPO autoantibodies, in the majority of cases of Graves' disease and Hashimoto's thyroiditis, including other variants of chronic primary hypothyroidism such as myxoedema and asymptomatic thyroiditis. They have also been detected in spontaneous or postpartum painless thyroiditis, in thyroid autoimmunity with rheumatoid arthritis, and in non-thyroid autoimmune diseases such as Addison's disease and type 1 diabetes mellitus.

Kallestad™ Anti-Thyroid Peroxidase (Anti-rTPO) Autoimmune EIA

Clinical Utility

Autoimmune thyroid disorders encompass autoimmune destruction and stimulation; both states are associated with predominantly IgG local and circulating thyroid autoantibodies.

Trotter et al.1 and Roitt et al.2 showed that many patients with advanced thyroiditis had antibodies for a thyroid antigen distinct from Tg (thyroglobulin). This was termed thyroid microsomal antigen (TMA). Considerable evidence indicates that TMA is antigenically related to thyroid peroxidase (TPO), a membrane-bound glycoprotein enzyme with an approximate mass of 101 kD, whose in vivo function is the iodination of tyrosine in the synthesis of the thyroid hormones T3 and T4. Anti-TPO antibodies are found, often in conjunction with anti-thyroglobulin autoantibodies, in the majority of cases of Hashimoto's thyroiditis and Graves' disease and in cases of primary myxoedema. The relationship of autoimmune thyroid disease in pregnancy has been the subject of considerable interest, with the demonstration of TPO antibodies in most cases of post-partum thyroid disease syndrome3–6 and the association of thyroid autoantibodies with increased miscarriage risk.7 Anti-TPO antibodies are found in other non-thyroid conditions, e.g. pernicious anemia,8,9 diabetes mellitus,10,11 rheumatoid arthritis,12 Addison's disease11 and Sjögren's syndrome.9 In addition, anti-TPO antibodies are detectable at low levels in 2–8% of apparently healthy individuals, particularly in the elderly and more often in women than in men, although the clinical significance of this is unclear.

This assay provides reproducible results through the use of DNA recombinant technology. This technology minimizes the potential of antisera to bind both to specific and unspecific thyroid cell components. The Bio-Rad Kallestad Anti-Thyroid Peroxidase Kit is made with human recombinant TPO antigen, which has been demonstrated to be highly specific for TPO autoantibodies. Additional features include a lower clinical cut-off, reflecting increased sensitivity and specificity, and a narrower measuring range, ensuring greater accuracy and precision.

The Kallestad™ Anti-Thyroid Autoimmune EIA kits are intended for the qualitative and quantitative determination of anti-thyroid autoantibodies in human plasma or serum. Anti-thyroglobulin (Anti-Tg) and anti-thyroid peroxidase (Anti-TPO) are two major autoantibodies implicated in autoimmune related thyroiditis and aid in the differential diagnosis of Hashimoto’s thyroiditis and Graves’ disease.

Bio-Rad offers a full range of individual antibody EIA assays, which can be used in conjunction with ANA and ENA assays to identify specific autoantibodies associated with autoimmune diseases. The Bio-Rad Autoimmune Systemic EIA product line features common assay protocol, common reagents, color-coded breakaway wells and easy automation.

Assay Characteristics

Sample dilution: 1:100

Sample volume: 10 µL

Incubation time: 60/30/30 minutes

Incubation temperature: room temperature (18–25°C)

Conjugate: Alkaline phosphatase

Substrate: Phenolphthalein monophosphate (PMP)

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For more than 15 years, Bio-Rad has made science education a major priority. To support this effort, the company has implemented a discount policy that allows high school and college teaching laboratories to purchase kits, instruments, reagents, and other equipment at preferred prices.

How do I apply for the education discount?

If you are an educator at the high school or college level, visit our Education Discount Policy page to establish an education account number.